The short version: the PCs won. From being barely able to hit Garrett in the previous session, they managed to overload him enough to hit him often. Larissa's magic missiles were a particular threat, and Garrett's wand of shield was easily overcome (and when he was recasting the shield, he wasn't attacking. And Garrett couldn't hit for beans--in two rounds in a row, he attacked Larissa 4 times and missed every time.
But it was a very good result. It was not an anticlimactic fight at all, and the players certainly felt excited and happy about the game. I think it's very plausible that having them win this evening was better pacing than it would have been for the night's battle to end inconclusively.
But I had to fight down disappointment after the session. I think the big reason was that I had so many other plans and fragments of plans that didn't come to fruition:
- The PCs had caught Garrett at a bad time; his first several rounds were spent trying to complete a ritual instead of engaging the PCs. A second fight would have had his full attention.
- Melisande could have cast cloudkill. I had it on her sheet and everything.
- I'd thought of having Melisande use telekinesis to yank away spellcasters' component pouches or trip and disarm fighters.
- I'd thought of Charlos pursuing Garrett somewhere beyond the PCs' reach, and having Garrett turn to disarm him of his ghost touch sword, and grin evilly that now the tables were turned. (Charlos would have been very indignant.)
- I'd thought of a subsequent fight in which the PCs confronted Garrett in the midst of a swarm of dominated children. The children would swarm towards the PCs, but when the domination was suppressed by their magic circle against evil, they would start screaming and whimpering in confusion and fear. (It's probably just as well that this got skipped; the hassles of dealing with the liberated kids would have been a problem.)
- I'd planned to have Charlos take over guarding Garrett's body in the castle, to provide more reason why he had to stay there. (I did remember the bit I'd planned for a long time of having the stake wither to a rotten toothpick as it penetrated--sadly, Kevin seemed to regard it as an inconvenience instead of a cool bit.)
But I've concluded that it's not so bad that these things didn't happen and that the vampires weren't more effective; the players were aware of the fearsome possibilities of things that could happen, and that added lots of excitement even though they didn't come true.
The night after the session was extremely rough for me, though, with lots of perfectionist recriminations of "I should have done X, or Y, or Z"--even though I knew that it had been a good session and a good result. I realized that I was being insane, that my thoughts were not rational--but realizing that was not sufficient for me to stop the irrationality. So I sought ways to just not think for a while, in hopes that my thoughts would untangle themselves--but sleep seemed difficult, walking would just give me more time to think by myself, and alcohol seemed like a ticket to more unhappy thoughts.
What finally helped me break out of my twisted thoughts was laughing about unrelated topics. i'll have to remember that as a technique the next time I identify my thoughts as irrational.